% 导言区
\documentclass{ctexart}

% \usepackage{ctex}

\newcommand\degree{^\circ}

\title{\heiti 论文}
\author{\kaishu 勇}
\date{\today}

% 正文区
\begin{document}
	\maketitle
	
	Hello World!
	% here is my big formual
	Let $f(x)$ be defined by the formula $$f(x)=3x^2+x-1$$ 
	
	which is a polynomial of degree 2.
	
	% 带编号的公式
	勾股定理，设直角三角形的三边$ABC$，其中$\angle C=90 \degree$，则有：
	\begin{equation}
		AB^2 = BC^2 + AC^2
	\end{equation}
	
	
\end{document}